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A few years ago, I built a movie projector out of LEGO. I posted pictures of it in Wikipedia.

In the notes that explain these images, I explain that the width of the film is 31.4 mm.

Is it the right width, taking into account the play necessary for the operation of the mechanism?

zovits
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Bernard de Go Mars
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  • Hi Bernard and welcome to Bricks.SE! This is a site focused on questions and answers about LEGO and other building bricks, but your question seems to be about the dimensions of a film strip, without any relevant connections to the LEGO system. Therefore I propose that your question be migrated to either Photography.SE or to Engineering.SE, where the community is better geared to answer this. – zovits May 07 '21 at 08:56
  • Hello zovits! The width of the film is conditioned by the thickness of four LEGO elements. This is why I am inquiring about the exact thickness of these elements ... It's a bit the same thing when you build steam machines out of LEGO: you use the round brick as a piston and you slide it into a syringe body ... Regards, ~ Bernard – Bernard de Go Mars May 07 '21 at 09:52
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    So if I understand correctly, you already know that the film strip is 31.4 mm wide, and that it is the same as four LEGO elements. What is the unknown variable? The exact dimensions of LEGO bricks? If so, here is an answer detailing just that. The last sentence about the steam machine and the syringe body is a bit confusing, I can't see how it is the same thing as advancing a film strip. – zovits May 07 '21 at 14:23
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    For other contributors: To see how the 4 elements width is to be understood in the context of this question, see the (mostly) LEGO model mentioned in the question here, found by following the links in the author's Wikipedia profile. – zovits May 07 '21 at 14:30
  • Sorry to say, but this question feels a bit fabricated to me in an attempt to create traffic to the author’s project. I fail to see the relevant question. Voting to close. – Phil B. May 08 '21 at 11:17
  • Hello everyone and hello and thanks to zovits for browsing to one of my sites and in particular to the page dedicated to my LEGO cinema projector.It is possible that my request for dimensions is a little too demanding (I would need the LEGO dimensions with the tolerances). In fact, I found a few years ago that a 31.4mm wide film would fit well into the LEGO construction, but, as an engineer reflex, I would obviously like to find the tolerance to add to this code. nominal 31.4. It may be a bit complicated if there is no document giving the tolerances of the LEGO parts... Thank you again! – Bernard de Go Mars May 08 '21 at 14:11
  • Hello Phil B. In French, we have an expression: "Do well and let people know". Both my cinema projector and my LEGO steam engines (these really working devices) are old projects. On my two sites, there is no advertising and I do not sell anything. These are only "sharing" sites (as is Wikipedia of which I am a frequent contributor). Having said that, I don't know the conventions of bricks.stackexchange.com and maybe my posts are not in accordance with them... I hope there is no offense. . There is just a great respect for mechanical LEGO constructions. Sincerely, Bernard – Bernard de Go Mars May 08 '21 at 14:24
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    Perhaps rewording your question entirely could change community's view. Something along the line of "I have a space of 4 studs. What is the maximum width of a film I can put into this gap?" would work. Adding pictures and explaining your issue in more details also helps to provide a clear answer/advise. – Alex May 08 '21 at 17:27
  • Thanks Alex. Perhaps the question I am asking is too technical, although in practice I have learned a lot from the links provided by you. My question concerns the dimensional tolerances used by the LEGO company for the manufacture of its parts. The "nominal" dimensions have their interest (but you can measure them yourself with a caliper) but the tolerances are even more interesting. The problem is that they cannot be measured since each piece in practice has a slightly different dimension. In fact it appears to me with delay that these tolerances are not public data... – Bernard de Go Mars May 09 '21 at 10:08

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